In such drive trains, it has been common up to now to place a lid on top of the drive train housing, on which lid the motor is fastened. The pinion provided on the motor shaft and the gear with which it mates are thus arranged within a kind of a trough or tank which is formed by the drive train housing. This arrangement has the disadvantage that, for various wheel widths, different housings and different lids are needed, which among other things is connected to high model, manufacturing and inventory costs. In the interest of satisfactory steering capability for the vehicle, it is desirable that the swivel axis of the drive train lie approximately in the central plane of rotation of the drive wheel. This requires, for different wheel widths, different axle bases for the spur gear stage and thus different housings and lids.
A basic purpose of the invention is therefore to improve a drive train of the above-mentioned type so that the same housing can be used for various wheel widths and, aside from different spur gears, only one part which can be easily adapted is needed in different applications.